Watering valves for animals such as hamsters, guinea pigs, chinchillas, rabbits, dogs, monkeys, and pigs have been in use for several years. A need for automatic watering valves for very small animals such as tiny weanling mice has developed due to the increased use of small animals in laboratories to test various foods and chemical substances. Attempts to merely scale down existing valves has resulted in failure. Scaled-down valves became clogged with mineral deposits or will not automatically shut off at lower operating pressures. Increasing the pressures solved the shut off problem but the weanling mice could not shut off the valve, however low water pressures result in complete flow stoppage when air became entrapped in the valve housing or supply lines. Unless the valves are automatically shut by a spring loaded device, bacteria can migrate back through one valve to the entire system.